Background:Black locust(BL,Robinia pseudoacacia)is considered a promising tree species for reforestation due to its great ability to fix nitrogen.However,after two or three coppice-harvesting rotations,the productivity of BL declines.Whether soil microbial communities are affected and how these groups correlate with the nitrogen mineralization process across multi-generation stands remains unclear.Methods:We investigated the composition and structure of free-living nitrogen-fixing microorganisms(diazo-trophs)by sequencing the marker gene nifH and compared these results to levels of soil nitrogen mineralization in the bulk soil and rhizosphere in black locust plantations on Mount Tai,China.Results:The results showed multi-generation BL coppice plantations decreased the total soil nitrogen(N),soil phosphorus(P),soil microbial biomass N(MBN),soil microbial biomass C(MBC),soil nitrification rate(Rn),soil ammonification rate(Ra),and net soil N mineralization rate(Rm),but significantly increased the concentration of soil NH4+-N to maintain sufficient NO3-N.The dominant species in bulk soil and rhizosphere changed from Rhodopseudomonas(22.62％and 15.76％),unclassified_c_Alphaproteobacteria(22.37％and 29.28％),unclassifie-d o_Rhizobiales(15.40％and 13.31％),Bradyrhizobium(12.00％and 11.74％)in seedling plantations to Bra-dyrhizobium(45.95％and 47.86％)and Rhodopseudomonas(43.56％and 41.84％)in coppice plantations,respectively.Mantel test and Redundancy analysis(RDA)revealed that Rn,Ra,and Rm were the most important factors shaping the diazotrophic communities.Conclusions:Our results suggest that the multi-generation BL coppice plantation can homogenize soil diazotrophic communities,which is mainly regulated by the available N loss caused by nitrogen mineralization.Strengthening the management technology of coppice plantations will provide more beneficial external consumption.

Kun Li;Huimei Tian;W.Keith Moser;Steven T.Overby;L.Scott Baggett;Ruiqiang Ni;Chuanrong Li;Weixing Shen

Mountain Tai Forest Ecosystem Research Station of State Forestry Administration,Key Laboratory of State Forestry Administration for Silviculture of the Lower Yellow River,Forestry College of Shandong Agricultural University,Tai'an 271018,Shandong,China;Rocky Mountain Research Station,United States Forest Service,2500 S.Pine Knoll Dr.,Flagstaff,AZ,86001,USA;Rocky Mountain Research Station,United States Forest Service,240 West Prospect Fort Collins,CO,80526,USA;Mount Tai Scenic Spot Management Committee,Tai'an,271000,Shandong,China

森林生态系统（英文版）

[1]Kun Li;Huimei Tian;W.Keith Moser;Steven T.Overby;L.Scott Baggett;Ruiqiang Ni;Chuanrong Li;Weixing Shen-.Black locust coppice stands homogenize soil diazotrophic communities by reducing soil net nitrogen mineralization)[J].森林生态系统（英文版）,2022(03):289-300

coppice,diazotrophic,trophs,ammonification,unclassifie,dyrhizobium

Black,locust,stands,homogenize,soil,communities,by,reducing,net,nitrogen,mineralization,Background,BL,Robinia,pseudoacacia,considered,promising,tree,species,reforestation,due,its,great,ability,However,after,two,three,harvesting,rotations,productivity,declines,Whether,microbial,affected,these,groups,correlate,process,across,multi,generation,remains,unclear,Methods,We,investigated,composition,structure,free,living,fixing,microorganisms,sequencing,marker,nifH,compared,results,levels,bulk,rhizosphere,black,plantations,Mount,Tai,China,Results,showed,decreased,total,phosphorus,biomass,MBN,MBC,nitrification,rate,Rn,Ra,Rm,but,significantly,increased,concentration,NH4+,maintain,sufficient,NO3,dominant,changed,from,Rhodopseudomonas,unclassified,Alphaproteobacteria,Rhizobiales,Bradyrhizobium,seedling,respectively,Mantel,test,Redundancy,analysis,RDA,revealed,that,were,most,important,factors,shaping,Conclusions,Our,suggest,which,mainly,regulated,available,loss,caused,Strengthening,management,technology,will,provide,more,beneficial,external,consumption

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